Field of the Invention
The present invention relates to diagnosis of ovarian cancer using lysophosphatidylcholine (16:0) and homocysteic acid, which are low-mass ions present in biological samples.
Description of the Prior Art
Ovarian cancer is a malignant tumor occurring in the ovaries and is most often found in women aged 50-70 years. According to cancer statistics in Korea in the year 2002, about 1,000-1,200 new ovarian cancer patients are diagnosed each year, and ovarian cancer is a gynecologic cancer that is the second most common after cervical cancer. Epithelial ovarian cancer accounting for about 90% of ovarian cancer is diagnosed after stage III of development in most cases, and thus patients with epithelial ovarian cancer have a very low 5-year survival rate of 40% or less.
Patients with ovarian cancer show slight symptoms, and about 60% of the patients visit hospitals after the cancer developed significantly. For this reason, it is recommended that women to be regularly examined for ovarian cancer about once a year, even if there are no symptoms of ovarian cancer. Methods that are currently used to diagnose ovarian cancer include the review of medical history and family history, the palpation of ovary, ultrasound examination, and a blood testing method for measuring whether the expression of CA125 biomarker increased. If a patient is suspected of having ovarian cancer, the cancer is identified by CT or MRI. However, these methods have disadvantages in that they can diagnose ovarian cancer only after the cancer developed significantly, may provide inaccurate diagnosis, and cause discomfort to patients during diagnosis.
Meanwhile, the spectra of ions in blood can be extracted using a MALDI-TOF spectrometer. Mass spectrometry used in conventional proteomic analysis was performed to analyze substances mainly in the mass range of 800-2500 m/z, because this range is the mass range of peptides cleaved from proteins by trypsin. In addition, the use of a MALDI-TOF mass spectrometer can also extract the mass spectra of low-mass ions. However, because the low-mass range of about 800 m/z or less is a range in which the peaks of a matrix that is an object to be analyzed coexist, studies on this range have not been actively conducted.
Mass spectra extracted using a MALDI-TOF mass spectrometer can be imported into MarkerView™ software and subjected to principal component analysis-based linear discriminant analysis (PCA-DA) using MarkerView™ software in order to diagnose ovarian cancer.